perl5181delta - what is new for perl v5.18.1


   This document describes differences between the 5.18.0 release and the
   5.18.1 release.

   If you are upgrading from an earlier release such as 5.16.0, first read
   perl5180delta, which describes differences between 5.16.0 and 5.18.0.

Incompatible Changes

   There are no changes intentionally incompatible with 5.18.0 If any
   exist, they are bugs, and we request that you submit a report.  See
   "Reporting Bugs" below.

Modules and Pragmata

   Updated Modules and Pragmata
   *   B has been upgraded from 1.42 to 1.42_01, fixing bugs related to
       lexical subroutines.

   *   Digest::SHA has been upgraded from 5.84 to 5.84_01, fixing a
       crashing bug.  [RT #118649]

   *   Module::CoreList has been upgraded from 2.89 to 2.96.

Platform Support

   Platform-Specific Notes
   AIX A rarely-encounted configuration bug in the AIX hints file has been

       After a patch to the relevant hints file, perl should now build
       correctly on MidnightBSD 0.4-RELEASE.

Selected Bug Fixes

   *   Starting in v5.18.0, a construct like "/[#](?{})/x" would have its
       "#" incorrectly interpreted as a comment.  The code block would be
       skipped, unparsed.  This has been corrected.

   *   A number of memory leaks related to the new, experimental regexp
       bracketed character class feature have been plugged.

   *   The OP allocation code now returns correctly aligned memory in all
       cases for "struct pmop". Previously it could return memory only
       aligned to a 4-byte boundary, which is not correct for an ithreads
       build with 64 bit IVs on some 32 bit platforms. Notably, this
       caused the build to fail completely on sparc GNU/Linux. [RT

   *   The debugger's "man" command been fixed. It was broken in the
       v5.18.0 release. The "man" command is aliased to the names "doc"
       and "perldoc" - all now work again.

   *   @_ is now correctly visible in the debugger, fixing a regression
       introduced in v5.18.0's debugger. [RT #118169]

   *   Fixed a small number of regexp constructions that could either fail
       to match or crash perl when the string being matched against was
       allocated above the 2GB line on 32-bit systems. [RT #118175]

   *   Perl v5.16 inadvertently introduced a bug whereby calls to XSUBs
       that were not visible at compile time were treated as lvalues and
       could be assigned to, even when the subroutine was not an lvalue
       sub.  This has been fixed.  [perl #117947]

   *   Perl v5.18 inadvertently introduced a bug whereby dual-vars (i.e.
       variables with both string and numeric values, such as $! ) where
       the truthness of the variable was determined by the numeric value
       rather than the string value. [RT #118159]

   *   Perl v5.18 inadvertently introduced a bug whereby interpolating
       mixed up- and down-graded UTF-8 strings in a regex could result in
       malformed UTF-8 in the pattern: specifically if a downgraded
       character in the range "\x80..\xff" followed a UTF-8 string, e.g.

           utf8::upgrade(  my $u = "\x{e5}");
           utf8::downgrade(my $d = "\x{e5}");

       [perl #118297].

   *   Lexical constants ("my sub a() { 42 }") no longer crash when

   *   Parameter prototypes attached to lexical subroutines are now
       respected when compiling sub calls without parentheses.
       Previously, the prototypes were honoured only for calls with
       parentheses. [RT #116735]

   *   Syntax errors in lexical subroutines in combination with calls to
       the same subroutines no longer cause crashes at compile time.

   *   The dtrace sub-entry probe now works with lexical subs, instead of
       crashing [perl #118305].

   *   Undefining an inlinable lexical subroutine ("my sub foo() { 42 }
       undef &foo") would result in a crash if warnings were turned on.

   *   Deep recursion warnings no longer crash lexical subroutines. [RT


   Perl 5.18.1 represents approximately 2 months of development since Perl
   5.18.0 and contains approximately 8,400 lines of changes across 60
   files from 12 authors.

   Perl continues to flourish into its third decade thanks to a vibrant
   community of users and developers. The following people are known to
   have contributed the improvements that became Perl 5.18.1:

   Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsker,
   David Mitchell, Father Chrysostomos, Karl Williamson, Lukas Mai,
   Nicholas Clark, Peter Martini, Ricardo Signes, Shlomi Fish, Tony Cook.

   The list above is almost certainly incomplete as it is automatically
   generated from version control history. In particular, it does not
   include the names of the (very much appreciated) contributors who
   reported issues to the Perl bug tracker.

   Many of the changes included in this version originated in the CPAN
   modules included in Perl's core. We're grateful to the entire CPAN
   community for helping Perl to flourish.

   For a more complete list of all of Perl's historical contributors,
   please see the AUTHORS file in the Perl source distribution.

Reporting Bugs

   If you find what you think is a bug, you might check the articles
   recently posted to the comp.lang.perl.misc newsgroup and the perl bug
   database at .  There may also be
   information at , the Perl Home Page.

   If you believe you have an unreported bug, please run the perlbug
   program included with your release.  Be sure to trim your bug down to a
   tiny but sufficient test case.  Your bug report, along with the output
   of "perl -V", will be sent off to to be analysed by
   the Perl porting team.

   If the bug you are reporting has security implications, which make it
   inappropriate to send to a publicly archived mailing list, then please
   send it to  This points to a closed
   subscription unarchived mailing list, which includes all the core
   committers, who will be able to help assess the impact of issues,
   figure out a resolution, and help co-ordinate the release of patches to
   mitigate or fix the problem across all platforms on which Perl is
   supported.  Please only use this address for security issues in the
   Perl core, not for modules independently distributed on CPAN.


   The Changes file for an explanation of how to view exhaustive details
   on what changed.

   The INSTALL file for how to build Perl.

   The README file for general stuff.

   The Artistic and Copying files for copyright information.


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